/*
 * Copyright (C) 2014 Cyril Hrubis chrubis@suse.cz
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <linux/loop.h>
#include <stdint.h>
#include <inttypes.h>
#include "test.h"
#include "safe_macros.h"

#ifndef LOOP_CTL_GET_FREE
# define LOOP_CTL_GET_FREE 0x4C82
#endif

#define LOOP_CONTROL_FILE "/dev/loop-control"

#define DEV_FILE "test_dev.img"
#define DEV_SIZE_MB 256u

static char dev_path[1024];
static int device_acquired;

static const char *dev_variants[] = {
	"/dev/loop%i",
	"/dev/loop/%i",
	"/dev/block/loop%i"
};

static int set_dev_path(int dev)
{
	unsigned int i;
	struct stat st;

	for (i = 0; i < ARRAY_SIZE(dev_variants); i++) {
		snprintf(dev_path, sizeof(dev_path), dev_variants[i], dev);

		if (stat(dev_path, &st) == 0 && S_ISBLK(st.st_mode))
			return 1;
	}

	return 0;
}

static int find_free_loopdev(void)
{
	int ctl_fd, dev_fd, rc, i;
	struct loop_info loopinfo;

	/* since Linux 3.1 */
	ctl_fd = open(LOOP_CONTROL_FILE, O_RDWR);

	if (ctl_fd > 0) {
		rc = ioctl(ctl_fd, LOOP_CTL_GET_FREE);
		close(ctl_fd);
		if (rc >= 0) {
			set_dev_path(rc);
			tst_resm(TINFO, "Found free device '%s'", dev_path);
			return 0;
		}
		tst_resm(TINFO, "Couldn't find free loop device");
		return 1;
	}

	switch (errno) {
	case ENOENT:
	break;
	case EACCES:
		tst_resm(TINFO | TERRNO,
		         "Not allowed to open " LOOP_CONTROL_FILE ". "
			 "Are you root?");
	break;
	default:
		tst_resm(TBROK | TERRNO, "Failed to open " LOOP_CONTROL_FILE);
	}

	/*
	 * Older way is to iterate over /dev/loop%i and /dev/loop/%i and try
	 * LOOP_GET_STATUS ioctl() which fails for free loop devices.
	 */
	for (i = 0; i < 256; i++) {

		if (!set_dev_path(i))
			continue;

		dev_fd = open(dev_path, O_RDONLY);

		if (dev_fd < 0)
			continue;

		if (ioctl(dev_fd, LOOP_GET_STATUS, &loopinfo) == 0) {
			tst_resm(TINFO, "Device '%s' in use", dev_path);
		} else {
			if (errno != ENXIO)
				continue;
			tst_resm(TINFO, "Found free device '%s'", dev_path);
			close(dev_fd);
			return 0;
		}

		close(dev_fd);
	}

	tst_resm(TINFO, "No free devices found");

	return 1;
}

static int attach_device(const char *dev, const char *file)
{
	int dev_fd, file_fd;
	struct loop_info loopinfo;

	dev_fd = open(dev, O_RDWR);
	if (dev_fd < 0) {
		tst_resm(TWARN | TERRNO, "open('%s', O_RDWR) failed", dev);
		return 1;
	}

	file_fd = open(file, O_RDWR);
	if (file_fd < 0) {
		tst_resm(TWARN | TERRNO, "open('%s', O_RDWR) failed", file);
		close(dev_fd);
		return 1;
	}

	if (ioctl(dev_fd, LOOP_SET_FD, file_fd) < 0) {
		close(dev_fd);
		close(file_fd);
		tst_resm(TWARN | TERRNO, "ioctl(%s, LOOP_SET_FD, %s) failed",
			 dev, file);
		return 1;
	}

	/* Old mkfs.btrfs use LOOP_GET_STATUS instead of backing_file to get
	 * associated filename, so we need to set up the device by calling
	 * LOOP_SET_FD and LOOP_SET_STATUS.
	 */
	memset(&loopinfo, 0, sizeof(loopinfo));
	strcpy(loopinfo.lo_name, file);

	if (ioctl(dev_fd, LOOP_SET_STATUS, &loopinfo)) {
		close(dev_fd);
		close(file_fd);
		tst_resm(TWARN | TERRNO,
			 "ioctl(%s, LOOP_SET_STATUS, %s) failed", dev, file);
		return 1;
	}

	close(dev_fd);
	close(file_fd);
	return 0;
}

static int detach_device(const char *dev)
{
	int dev_fd, ret, i;

	dev_fd = open(dev, O_RDONLY);
	if (dev_fd < 0) {
		tst_resm(TWARN | TERRNO, "open(%s) failed", dev);
		return 1;
	}

	/* keep trying to clear LOOPDEV until we get ENXIO, a quick succession
	 * of attach/detach might not give udev enough time to complete */
	for (i = 0; i < 40; i++) {
		ret = ioctl(dev_fd, LOOP_CLR_FD, 0);

		if (ret && (errno == ENXIO)) {
			close(dev_fd);
			return 0;
		}

		if (ret && (errno != EBUSY)) {
			tst_resm(TWARN,
				 "ioctl(%s, LOOP_CLR_FD, 0) unexpectedly failed with: %s",
				 dev, tst_strerrno(errno));
			close(dev_fd);
			return 1;
		}

		usleep(50000);
	}

	close(dev_fd);
	tst_resm(TWARN,
		"ioctl(%s, LOOP_CLR_FD, 0) no ENXIO for too long", dev);
	return 1;
}

const char *tst_acquire_device__(unsigned int size)
{
	int fd;
	char *dev;
	struct stat st;
	unsigned int acq_dev_size;
	uint64_t ltp_dev_size;

	acq_dev_size = MAX(size, DEV_SIZE_MB);

	dev = getenv("LTP_DEV");

	if (dev) {
		tst_resm(TINFO, "Using test device LTP_DEV='%s'", dev);

		if (stat(dev, &st)) {
			tst_resm(TWARN | TERRNO, "stat() failed");
			return NULL;
		}

		if (!S_ISBLK(st.st_mode)) {
			tst_resm(TWARN, "%s is not a block device", dev);
			return NULL;
		}

		fd = open(dev, O_RDONLY);
		if (fd < 0) {
			tst_resm(TWARN | TERRNO,
				 "open(%s, O_RDONLY) failed", dev);
			return NULL;
		}

		if (ioctl(fd, BLKGETSIZE64, &ltp_dev_size)) {
			tst_resm(TWARN | TERRNO,
				 "ioctl(fd, BLKGETSIZE64, ...) failed");
			close(fd);
			return NULL;
		}

		if (close(fd)) {
			tst_resm(TWARN | TERRNO,
				 "close(fd) failed");
			return NULL;
		}

		ltp_dev_size = ltp_dev_size/1024/1024;

		if (acq_dev_size <= ltp_dev_size)
			return dev;

		tst_resm(TINFO, "Skipping $LTP_DEV size %"PRIu64"MB, requested size %uMB",
				ltp_dev_size, acq_dev_size);
	}

	if (tst_fill_file(DEV_FILE, 0, 1024, 1024 * acq_dev_size)) {
		tst_resm(TWARN | TERRNO, "Failed to create " DEV_FILE);
		return NULL;
	}

	if (find_free_loopdev())
		return NULL;

	if (attach_device(dev_path, DEV_FILE))
		return NULL;

	device_acquired = 1;

	return dev_path;
}

const char *tst_acquire_device_(void (cleanup_fn)(void), unsigned int size)
{
	const char *device;

	if (device_acquired) {
		tst_brkm(TBROK, cleanup_fn, "Device already acquired");
		return NULL;
	}

	if (!tst_tmpdir_created()) {
		tst_brkm(TBROK, cleanup_fn,
		         "Cannot acquire device without tmpdir() created");
		return NULL;
	}

	device = tst_acquire_device__(size);

	if (!device) {
		tst_brkm(TBROK, cleanup_fn, "Failed to acquire device");
		return NULL;
	}

	return device;
}

int tst_release_device(const char *dev)
{
	int ret;

	if (getenv("LTP_DEV"))
		return 0;

	/*
	 * Loop device was created -> we need to detach it.
	 *
	 * The file image is deleted in tst_rmdir();
	 */
	ret = detach_device(dev);

	device_acquired = 0;

	return ret;
}

int tst_clear_device(const char *dev)
{
	if (tst_fill_file(dev, 0, 1024, 512)) {
		tst_resm(TWARN, "Failed to clear 512k block on %s", dev);
		return 1;
	}

	return 0;
}

int tst_umount(const char *path)
{
	int err, ret, i;

	for (i = 0; i < 50; i++) {
		ret = umount(path);
		err = errno;

		if (!ret)
			return 0;

		tst_resm(TINFO, "umount('%s') failed with %s, try %2i...",
		         path, tst_strerrno(err), i+1);

		if (i == 0 && err == EBUSY) {
			tst_resm(TINFO, "Likely gvfsd-trash is probing newly "
			         "mounted fs, kill it to speed up tests.");
		}

		usleep(100000);
	}

	tst_resm(TWARN, "Failed to umount('%s') after 50 retries", path);
	errno = err;
	return -1;
}